Self elevating formwork installation with variable geometry for making concrete surfaces, particularly very high concrete surfaces

ABSTRACT

A self-elevating formwork for making concrete walls. The apparatus includes means for temporarily fixing working platforms to previously cast wall portions and is characterized by upright members having a pivot on one side and elevation adjustment means on the opposite side.

The present invention relates to self elevating formwork installationswith variable geometry for making concrete walls, in particular walls ofgreat height, these walls being formed by successive lifts of constantheight, carried out practically simultaneously, successively or inblocks over the whole length of the work until the desired height isobtained, this installation comprising essentially means for temporarilyfixing working platforms over an underlying part of the wall alreadycast and hardened, means for shuttering the next lift over saidunderlying part, and elevating means adapted to provide self elevationof the whole of the working platforms.

The aim of the present invention is to provide such an installationwhich allows thin walls made from self stable reinforced concrete to beerected better and more rapidly than the installations known up topresent, and in particular walls of great height with a generallycircular cross section and with evolutive geometry, as in the case inparticular of high cooling towers in the form of hyperbolids ofrevolution.

Such an installation will then have to allow the construction of theformwork forming the mold for giving to the wall the desired shape, andit will further have to allow means to be obtained for the support andself elevation of the different scaffoldings giving access to all theparts of the work under construction, and all the necessary operationsto be carried out, namely reinforcement, shuttering, concrete work aswell as the control of all the moving mechanical parts.

In particular, an installation in accordance with the invention willalso have to allow the extremely accurate adjustment of the differentslopes of the wall to be formed, by actuating means for adjusting thesuccessive and relative slopes of the different elements of the shutterwork.

As for the assemblies of the working platforms, they will have to bealso very simply adaptable to the variations of the radius of thecurvature of the work under construction, this radius of curvatureundergoing extremely large variations from the base to the top of thetower under construction.

All these aims, as well as others which will appear from reading thefollowing description, are attained by means of an installation of thegeneral type defined at the beginning in which, in accordance with thepresent invention will be essentially characterized in that said fixingmeans comprise series of main uprights extending substantially invertical planes, these series being evenly spaced apart along the lengthof the wall, said main uprights serving essentially, on the one hand, aselements for maintaining in position the forms of the shutter work, and,on the other hand, as means for guiding and securing mobile selfelevating brackets supporting said working platforms.

Hereagain, the following description better reveals how the aims soughtmay be attained with the above generally defined means.

In any case an essential arrangement of the present invention such asdefined above and which largely contributes to reaching these aims,resides in the multiple role played by what was designated above by thename "main uprights", these uprights serving on the one hand asevolutive supports for the shutter work elements and on the other handas guide and securing means for the mobile self elevating brackets,which support the working platforms.

According to an essential complementary arrangement of the presentinvention, in each series of main uprights it is provided that alluprights, except for the upper upright, are anchored in the cast andhardened concrete of a certain number of preceding lifts.

This arrangement will guarantee an excellent fixing of the series ofmain uprights on the already hardened concrete, which is essentially forthe safety of the personnel, as well as for the accuracy in positioningthe shutter work.

The evolutive character of the uprights, namely their ability to beappropriately orientated in the radial direction will result in thecomplementary arrangement according to which each series of mainuprights comprises a number of uprights situated in the same verticalplane, directly superimposed and hinged to each other, and each of whichis slanted through a given angle with respect to the adjacent upright.

Thus, besides securing the shutter work, the main uprights allowaccurate radial adjustment thereof.

As will be seen further on also, the structure of these main uprightsmay be in addition such that they may compensate very readily for thetangential contraction of the shutter work panels, besides serving asguide and securing rails for the mobile brackets.

In any case, it is a question here of essential strengthening elementsadapted to take up the radial and tangential stresses of the concreteand transmitting to the preceding lift all the stresses which theyreceive.

An installation according to the present invention may be furthercharacterized in that it comprises in addition transfer means adaptedfor actuation after casting and to transfer the lower main upright ofeach of said series of uprights into a position situated above and inthe alignment of the main upper upright of the series considered, inwhich position said transferred upright may then be fixed, with thedesired slope with respect to the main upright immediately underneath,by using appropriate adjustment means.

Each main upright, in each series of main uprights, may thus be used alarge number of times by passing from a lower position in the series toan upper position in the same series when it is no longer useful at thebottom of the series.

Hereagain, this sequential transfer of the lower uprights to the upperpart of the series of uprights will be better understood hereafter.

A more or less large number of main uprights may be provided in each ofthe above mentioned series, but it will be particularly appropriate,hereagain according to an advantageous complementary arrangement of thepresent invention, to have four uprights in each of the series of mainuprights, each series of uprights then being anchored in the cast andhardened concrete of three precedng lifts, which is sufficient toprovide excellent fixing safety.

As for the means for adjusting the slope of a main upright with respectto the adjacent main upright, they may be formed in different ways, but,according to a particularly reliable inmplementation allowing readyadjustment, these adjustment means may comprise, on the one hand, atboth ends of said main uprights a first screw spacing adjustment deviceor similar, opposite a transverse hinging means and, on the other hand,a keying system or similar, adapted to lock two main adjacent uprightswith a relative slope once they have been adjusted.

According to another particularly advantageous arrangement of theinvention, the installation may be further characterized in that saidshutter work means comprise, in cooperation with the upper uprights ofsaid series of main uprights, secondary uprights inserted, on each sideof the wall, between two series of main adjacent uprights.

These secondary uprights may cooperate efficiently in securing theshutter work elements, concurrently with the main upper uprights of eachseries, besides allowing compensations to be made, like these latter,for the tangential contraction of the shutter work panels.

Furthermore, it is apparent that the use of such secondary uprightsinserted between the series of main uprights will divide by two the spanbetween two adjacent series of main uprights, without for all thathaving to double the number of these series.

In addition, it will be advantageous and convenient to fix eachsecondary upright to the main upper upright which is facing it by meansof a set of fixing rods passing through the space provided for the nextcasting.

Moreover, since said secondary upright may be recovered at each lift, itwill be advantageous for each of them to be extended at its lower end bya hinged extension, whose slope with respect to the secondary uprightproperly speaking is adjustable.

With such an extension, the secondary upright may be fixed to the lowerlift after the concrete has set; it will further allow the slope of thesecondary upright concerned to be adjusted with respect to thispreceding lift; and it will finally allow, if required, to provide atangential compensation,towards the outside of the wall (convex side) sothat the shutter work will be always completed vertically.

Turning to the self elevating mobile brackets which, as was mentionedabove, are intended to support the working platforms and which may beguided and secured to said main uprights, in accordance with anotheradvantageous embodiment of the present invention they will beadvantageously provided in the form of hinged parallelogram structures,these structures being associated with means for adjusting theirdeformation, which may be actuated depending on the slope of the part ofthe wall to be shuttered, these means being adapted to maintain saidworking platforms constantly horizontal.

Theoretically, each bracket may comprise main front stringers hingedlyconnected, by means of bearing cross pieces, to secondary rearstringers, said deformation adjustment means being formed by screw orsimilar adjustment stays extending diagonally between main and secondarystringers.

Said bearing cross pieces may comprise, on the one hand, first crosspieces at the level of landings theoretically indeformable, theselandings providing passage from one platform to the adjacent platform atthe same level, and second cross pieces supporting the platformsrespectively at the same level as said landings, but disposed above thepreceding ones.

Considering the above explanations and the number of main uprights ineach series, each bracket may comprise three landings, two neighboringbrackets consequently supporting three levels of working platforms.

It will be further advantageous for each of said landings to have acommunicating trap door, for passing from one level to the adjacentlevel, more especially for passing main uprights and other equipmentfrom one level to another.

The brackets of an installation in accordance with the invention may befurther characterized by the fact that they each comprise on the onehand a fixed arm disk, disposed between the main stringers and adaptedto bear against the corresponding main upright and, on the other hand, amobile motor driven arm, adapted to be guided on the one hand betweenthe main strings of the bracket and, on the other hand, over saidcorresponding main upright and also to bear, at a given location, onsaid main upright.

As will be clear from reading what follows, the fixed and mobile arms ofeach bracket will cooperate so as to subject this latter to selfelevation when passing from one lift to the next left.

It may be further advantageous for each bracket to comprise anadditional bearing device--roller or similar--which is disposed at itslower part so as to be able to bear directly against the wall.

In any case, the brackets also form essential elements of aninstallation in accordance with the invention, for supporting thedifferent walk ways and working platforms while maintaining themconstantly horizontal, not withstanding the different slopes of the wallduring construction, and in addition, while serving as working cagesparticularly for recovering the lower main upright and repositioning itthree lifts higher, they form an automatic climbing system at each newlift.

These brackets will in general support three working levels, namely,from top to bottom, a reinforcing and concrete work level, a shutteringand shuttering removal level and finally a climbing level.

Finally, the platform assemblies will have to fulfill essentially theirrole of working and passage floor, while adapting themselves exactly andautomatically, in so far as their length is concerned to the essentiallyvariable spacings which occur between two adjacent brackets, because ofthe variable radius of curvature of the concrete wall, when it is aquestion of a cooling tower in the shape of a hyperboloid.

To this end, it will be advantageous, in accordance with yet anotherarrangement of the invention, for each platform to have a lower platformchassis and an upper platform chassis, extending between and bearing ontwo adjacent brackets, these two chassis being free to slide withrespect to each other.

For this arrangement, said lower platform chassis may in addition beformed from a frame bearing on a bracket and a beam bearing on theadjacent bracket, said beam being slidingly connected to said frame, andin that said upper platform chassis is mounted for bearing, on the onehand, on the same bracket as said beam and, on the other hand, alsoslidingly on the lower platform.

One embodiment of the invention will now be described, by way of examplewhich is in no wise limitative, with reference to the Figures of theaccompanying drawing in which:

FIG. 1 is a top view of a concrete wall during construction, with oneach side of this wall an assembly of two brackets and their platforms,which are in their position of maximum extension;

FIG. 2 is a view similar to that of FIG. 1, but in which said platformsare in their position of minimum extension;

FIG. 3 is a simplified prospective view of a part of the concrete wallduring construction, showing the setting up of the series of mainuprights, on the one hand, of the secondary uprights, on the other andthat of the shutter work;

FIG. 4 is a profile view of the wall of FIG. 3, equipped with itsuprights and shutter work;

FIG. 5 is an elevational front view of a main upright;

FIG. 6 is a profile view of the main upright of FIG. 5;

FIG. 7 is a partial detailed view, in section perpendicular to thehinged access, of the means for adjusting the relative slope of twoadjacent main uprights;

FIG.8 is a partial view in section through line VIII--VIII of FIG. 7;

FIG. 9 is a top view of the key;

FIG. 10 is a schematical elevational view with, for the sake of clarity,an exaggeration of the slopes of the main uprights and of their widths,showing the participation of the uprights in shuttering the walls;

FIGS. 11a to 11c are, with similar voluntary exaggeration of the slopes,partial and schematic profile biews showing different possible relativeslopes between two adjacent main uprights of the same series, dependingon the geometry of the part of the wall to be formed (positive slopeportion; vertical portion; negative slope portion);

FIGS. 12a to 12c are, with further voluntary exaggeration of the slopes,schematical profile views showing the shape assumed by the mobilebrackets depending on the slope of the part considered of the wall(positive slope; vertical portion; negative slope);

FIG. 13 is a front elevational view of a secondary upright;

FIG. 14 is a profile view of of the secondary upright of FIG. 13;

FIG. 15 is a partial detail view in section showing the hinging of anextension of a secondary upright and the means for adjusting the slopethereof with respect to the upright properly speaking;

FIG. 16 is a front elevational view of the secondary upright of FIG. 15;

FIG. 17 is a simplified view in axial section of a mobile self elevatingbracket in the vertical position;

FIG. 18 is a sectional view though the line XVIII--XVIII of FIG. 2 butshowing two deformed brackets situated on each side of a sloping portionof the concrete wall, these brackets extending as a whole along twovertical planes, but which are offset laterally with respect to eachother;

FIG. 19 is a top view of a lower platform chassis;

FIG. 20 is a sectional view through line XX--XX of FIG. 19;

FIG. 21 is a sectional detail view through line XI--XI of FIG. 20;

FIG. 22 is a top view of an upper platform chassis;

FIG. 23 is a profile view of the chassis of FIG. 22;

FIG. 24 is a detail view in section through line XIV--XIV of FIG. 22;and

FIGS. 25a to 25e are schematical profile views of a bracket (assumed tobe on a vertical portion of the wall), showing the different steps ofpassing from one lift to the next.

It will be assumed in what follows that the installation of theinvention which will be described is used for erecting a cooling or aircooling tower of the type generally used for cooling water in thermal ornuclear power stations.

They are concrete towers of very great height (up to more than a 100meters for some), formed of an extremely thin self supporting wall,having the general shape of a hyperboloid of revolution, and so withevolutive geometry, not only in so far as the slopes are concerned whichmay be positive or negative but also in so far as the radii of curvatureof the work are concerned which are essentially variable from the baseto the top.

An installation in accordance with the present invention will beparticularly well adapted to the erection of such towers, either bysimultaneous or immediately successive lifts over the whole periphery ofthe work, or by lifts carried out in blocks.

In the different Figures, the concrete walls being erected is designatedby the reference 1.

The series of main uprights carrying the overall reference 2 (FIGS. 1and 2, these uprights being designated respectively, in each series, andfrom top to bottom, 2₁, 2₂, 2₃, and 2₄, taking into account that in thepresently described example the number of main uprights in each series 2is four (see particularly FIGS. 3, 4 and 25). The series 2 extend invertical planes and are evenly spaced apart, generally along the wholeperiphery of the wall 1, and on each side thereof, their spacing apartwhich is constant at a given level but essentially variable depending onthe height of the level considered being of the order of several meters.

As can be seen in FIGS. 3 and 4, only the three lower uprights 2₂, 2₃,and 2₄ of each series 2 are anchored in the hardened underlying concreteof wall 1, by means of traversing anchorage and securing rods referenced3, namely two rods 3 per main upright. The holes for passing thesesecuring and anchoring rods therethrough have been referenced at 4 inFIG. 5; they are formed at the level of U shaped reinforcement brackets5.

In each series 2, the upper main upright 2₁, serving for shuttering thenext lift, is firmly secured to the immediately underlying main upright2₂, as well as to a secondary upright 6 which faces it on the other sideof wall 1 by means of two fixing rods 7. Each secondary upright 6 isextended downwardly by a hinged extension of the same width 6' by meansof which it may be fixed to the underlying portion of hardened concrete1, by means of another securing and anchoring rod 3', which serves atthe same time as upper fixing means for the corresponding main upright2₂ (FIG. 4).

The fixing rods 7 and 3', which may be threaded bars, have also beenshown in FIG. 14 and the holes (elongate) through which they extend inthe secondary upright 6 and its extension 6' have been referenced 8 and8' in FIG. 13 (see also FIG. 15).

As can be clearly seen in FIGS. 1 to 4 and in accordance with animportant arrangement of the present invention, on a given face of thewall, each secondary upright 6 is inserted halfway between two series ofadjacent main uprights 2. In other words, and considering what hasalready been said, this arrangement is further characterized by the factthat said series 2 of main uprights of one face of the wall 1 are offsetwith respect to the series 2 of main uprights on the other face, by halfthe distance which on the same face separates two adjacent series, sothat each secondary upright 6 on one side of the wall is situatedopposite the upper upright 2₁ of the corresponding series 2 of mainuprights situated on the other side of wall 1. That reduces the spacingbetween two consecutive bearing points of the shutter-work forms withoutfor all that increasing the number of series 2 of main uprights.Furthermore and although with a relatively limited number of series ofmain uprights, the number of the sides of the superimposed polygonswhich will form wall 1 may thus be multiplied by 2 and so a circularsection may be closely approximated for a lower cost.

The shutter work forms are clearly shown in FIGS. 3 and 4 and have beenreferenced at 9 (see also FIG. 25). Each form is mounted and fixedbetween an upper main upright 2₁ and a secondary upright 6.

At the level of the upper uprights 2₁ the forms 9 are fixed by means ofwedges jammed between bar bolts shown schematically at 10 and crosspieces 11 of the forms. These bar bolts 10 pass through square tubes 12welded to the outside of the main uprights 2 and shown in FIGS. 5 and 6.

At the level of the secondary upright 6, the forms 9 are fixed by screwbolts shown schematically at 13 and similarly providing the desiredfixing between the cross pieces 11 of forms 9 and the secondary upright6. The fixing nuts of the screw bolts are shown schematically in FIGS.13 and 14, respectively at 14 for the secondary upright 6 and at 14' forits extension 6'.

As can be seen in FIGS. 5 and 6, each main upright 2₁ . . . 2₄ in so faras its structure is concerned, comprises two guide rails 15 made frommetal sheet bent into an L, connected transversely together by a widemetal sheet 16, developed over the whole of the height and forming atthe same time a compensation surface for the shutter work and resistancecaissons. At the top and at the bottom the assembly is closed by twometal sheets 17 bent back in the plane of the guide rails 15 (see alsoFIGS. 7 and 8).

Each main upright is moreover equipped, at its upper end and at itslower end, with coupling means for connecting it to an adjacent mainupright, as already mentioned above, as well as appropriate adjustmentmeans for accurately adjusting the slope of the upper main upright withrespect to that of the immediately underlying main upright. It will bereadily understood that the coupling means provided at both ends of amain upright are complementary; they are shown then as a whole on asingle upright, particularly in FIGS. 5 to 8.

These means comprise, at the lower part of each upright, a pin 18adapted to engage in an upper opening 19 of the cooperating main uprightand to be locked therein by means of a key 20 whose shape in section canbe seen in FIG. 9. This key may be locked between the bottom of the eyeof pin 18 and the upper bent back metal sheet 17, when the adjustment ofthe relative spacing between the two uprights has been performed. Theseuprights may in fact pivot with respect to each other about a round bar21 serving as transverse hinge shaft which allows adjustment of theradial slope of the main upper upright, of course at the desired moment,in each of the series 2 of uprights.

The first spacing adjustment device comprises for this purpose, at oneend of the upright, two pairs of gusset plates 22, each pair receivingthe two ends of a screw 23 with spacing adjustment nut 24, the twogusset plates 22 associated with an upright are hingedly connectedthereto by means of removable pins 25, each mounted in a fixed clevis26.

With this device, the ends of two main uprights may be rapidly separatedand joined together again when it is required to cause a lower mainupright to pass above the other three, and it also allows the upper mainupright which has just been placed in position to be conveniently andrapidly adjusted in the radial direction.

Finally, there are further shown at 27 in FIGS. 5 to 7 holes (three permain upright) for passing pins there-through for supporting the bracketsand at 28 flat bars for reinforcing the caisson structure of theuprights.

As for the secondary uprights 6, which may be recovered at each lift andwhose purpose is essentially to contribute to the form work, without anessential strengthening function, and which are adjustable only in theradial plane, they are formed by a channel bar shown at 29, welded flaton a wide bottom metal sheet 30, which allows a certain tangentialcompensation of the shuttering panels to be obtained, which have aheight which may for example be of the order of 1.50 m.

This contribution of the metal sheet 30 of these secondary uprights 6 tothe shutter work, concurrently with the forms 9, allows, like that ofthe bottom metal sheet 16 of the main uprights, shuttering to beavailable which is always sufficient even for wide variations of thegeometry of the wall, without requiring constant adjustment of thedimensions of the forms, which avoids losses of material and the sawingoperations which would be otherwise indispensable, as is the case inknown techniques.

As was mentioned above, each secondary upright 6 is provided at itslower end with an extension 6' for securing it to the solid concrete ofthe underlying casting, for possibly compensating the shutter work andfinally for allowing ready adjustment of the slope of the upright 6concerned with respect to said casting.

This extension 6' has a shape similar to that of upright 6 and ispivotably connected thereto by a simple metal sheet 13₁ welded to theinside of the bottom metal sheet 30. At its upper part, each secondaryupright 6 is provided with a lifting ring 32 and, at its lower part,with a second spacing adjustment device, comprising a screw 33. Thisscrew is held in position by a head ring 34 and a pin 35 passing througha clevis 36 of the secondary upright 6 and engages in a hole of atransverse metal sheet 37 of the extension 6'. Two nuts 38 engaged onscrew 33 clamp the metal sheet 37 and thus allow the relative spacingbetween uprights 6 and its extension 6' to be readily adjusted.

By way of indication, it may be noted that for a height of 1.5 m of thesecondary upright 6 the extension 6' may have a height of the order of0.45 m.

In FIGS. 1 and 2, the brackets have been shown generally at 39; they arealso described in detail in FIGS. 17 and 18. They are each constructedin the form of hinged parallelogram structures, which are formed fromtwo main front stringers 40 connected hingedly by bearing cross piecesto secondary rear stringers 41. The main stringers 40 are connectedtogether by rigid cross pieces 40' and the secondary stringers 41 bywind bracers 41' so as to form a rigid working cage which can only bedeformed in the radial plane, as a function of the slope of wall 1 andadjustably.

As for the above mentioned bearing cross pieces they comprise threepairs of first cross pieces 42₁, 42₂ and 42₃ situated on the oppositesides of each bracket 39 and respectively at the level of threeindeformable landings 43 made from metal sheet welded to trimmer beams,equipped with parapets 44, these landings provide passage at threedifferent levels through each bracket 39, for passing from one platformto the next (see also FIGS. 1 and 2). These landings 43 are moreovereach equipped with a trap door 45 for passing equipment therethrough,and more especially the main uprights 2₁ . . . 2₄ for the lower level(lever 3) to the upper level (level 1).

Said bearing cross pieces further comprise three second cross pieces46₁, 46₂, 46₃ disposed on one side of each bracket, also hinged to thestringers 40 and 41 and situated at a level lower than that of thepreceding ones. These cross pieces serve as supports for the platformpins which will be described hereafter, the platforms bearing on oneside on these second cross pieces and on three of the first cross piecesand on the other side on the other three first cross pieces.

Between each main stringer 40 and the secondary stringer 41 which facesit, in each bracket 39, there further extends a screw adjusting stay orstrut 47 for deforming appropriately the hinged parallelograms formingthe structure of the brackets, as can be seen by comparing FIGS. 17 and18, so that they are always parallel to the concrete wall 1 whilemaintaining the horizontality of the platforms at each of their threelevels. These screw stays 47 are hinged in gusset plates 47' of the mainand secondary stringers.

At 48 there is further shown an additional roller bearing device orsimilar 48, which is disposed at the lower end of each bracket 39 andbears on wall 1 while transmitting directly thereto the normalcompression forces.

Each bracket 39 comprises finally two members essential to itsoperation, and more especially to its self-elevating function, namely afixed arm 49 mounted between the two main stringers 40 and a mobile arm50, also shown in FIGS. 1 and 2 and capable of moving along thesestringers, above the fixed arm 49. It is through this mobile arm 50 thateach bracket 39 is guided along the corresponding series 2 of mainuprights, the mobile arm being for this purpose provided with tworollers 51 bearing behind the flanges of the main uprights, whichflanges consequently receive the normal forces of the mobile arm, otherrollers guiding it between the main stringers 40 of the bracket.

The mobile arm 50 is moved by a motor 52 bolted to a cross piece 40'connecting together the two main stringers 40 and rotating a screw 53axially fixed to the mobile arm.

Motor 52 may rotate in both directions so that the relative movementbetween the mobile arm 50 and bracket 39 may take place in one directionor in the other, for a purpose which will be described here below.

It should be noted that with the same end in view the fixed arm 49 maybear on a main upright through a pin 54 (see also FIGS. 17 and 18),engaged in two through holes 27 in the upright considered, an additionalpin 54 engaged in the two immediately lowered through holes providingthe security. Said pin 54 receives the tangential forces from the fixedarm 49.

Similarly, the mobile arm 50 may bear on a main upright through a pin 55engaged in two other through holes 27 (above the preceding ones) in theupright considered.

The structure of the platforms is shown in FIGS. 19 to 24 but can alsobe seen in FIGS. 1 and 2. Each platform comprises a lower platformchassis 56 (FIGS. 19 to 21) and an upper platform chassis 57 (FIGS. 22to 24).

The lower chassis 56 is formed by a frame 48 bearing on a bracketcross-piece 42₁ (or 42₂ or 42₃), and a pin 59 whose end bears on across-piece 46₁ (or 46₂ or 46₃) of the adjacent bracket, this lattercross-piece being at a level slightly lower than that of the first one.This pin 59 is mounted for sliding by its other end in a cradle 60 fixedunder the end of frame 58 which is opposite the end bearing oncross-piece 42₁. Any variation in the spacing between supports 42₁ and46₁, i.e. any variation of the radius of curvature of wall 1, will thenresult in pin 59 sliding with respect to the frame 58 of the lowerchassis structure 56.

The upper platform chassis 57 is formed from a frame bearing, on the onehand, on a bracket cross piece 42₁ (the one situated above the abovementioned cross piece 46₁) and, on the other hand, and also slidingly,on the lower chassis 56.

Thus the length of the platform may be very conveniently andautomatically obtained tangentially between two adjacent brackets 39,without any loss of material and without any complicated mechanism, ascan be readily seen from comparing FIGS. 1 and 2 (maximum spacing apartin FIG. 1 and minimum in FIG. 2).

The construction of the upper and lower platform chassis may be asfollows.

The upper chassis 57 is formed from two shafts 61 connected together bymetal cross pieces 62.

The bearing cross piece 42₁ is provided with a gusset plate having afixing hole 63 along the anchoring access to bracket 39, allowingrotation thereof in a horizontal plane. The ends of shafts 61 bearing onbracket 39 are provided with two transversely disposed round portions 67for rotation in the vertical plane and slight sliding in the horizontalplane.

Along these shafts 61 are fixed fittings 64-66 for fixing the planking65 and a removable parapet (not shown).

The frame 58 of the lower chassis 56 is constructed identically to theupper chassis.

Cradle 60 is formed by two cross pieces 68 connected to the shafts 69. Across piece 70 forms the support under compression (at the end). Theother is associated with a cradle 71 supporting beam 59 under traction.The assembly forms a sliding housing 71-46₁.

The "beam 59-cross piece 46₁ " contact points are provided with slidingteflon bearing portions. Beam 59 is formed from two longitudinalelements 72 connected together by transverse stiffeners 73.

At the end of the bearing points of beam 59 on bracket 39 is provided ananchorage key fixing the beam to this bracket in free vertical rotation.

FIG. 10 shows schematically the possibility of a certain tangentialcompensation of the form work by the flanges of the main upright 2,which has already been mentioned above.

FIGS. 11a to 11c also show schematically three different relativepositions of slope between two successive main uprights and FIGS. 12a to12c also show schematically three different slope positions of themobile brackets 39, which may thus be always parallel to the wall 1 withthe platforms remaining horizontal.

The operations for self elevation of brackets 39 take place in thefollowing way, from a starting position such as the one shownschematically in FIG. 25a: the motor 52 is set in rotation in adirection such that, through its groove 53, it causes the mobile arm 50to rise as far as the position shown in FIG. 25b. Pin 55 is withdrawnfrom its first position in upright 2₄ for engagement in the throughholes 27 in upright 2₃, under the bracket 50; with the upper lifthardened, the forms 9 are withdrawn, on each side of wall 1).

The motor 52 is then caused to rotate in the opposite direction, whichcauses bracket 39 to rise which bears on the main upright 2₃ through themobile arm 50. This rise is stopped when it reaches 0.75 m, the fixedarm 49 being then located at a level such that, through a pin 54, it maybe held in position bearing on the lower through hole 27 of upright 2₃(FIG. 25c). The lower main upright 2₄ may then be separated from wall 1and lifted by transfer means (hoists or similar), through trap doors 45in landings 43, to the upper level of the bracket, where it may then bepositioned for carrying out a new lift.

Then motor 52 is caused to rotate in the same direction as previously soas to cause bracket 39 to rise again over 0.75 m and to bring it into aposition (FIG. 2d) in which the fixed arm 49 may be clamped on thethrough holes 27 of upright 2₃, situated immediately below those whichlock the mobile arm 50.

By thus raising the mobile arm 39 over 1.50 m, but in two steps, slopesof the platforms which are too great may be avoided if the raising oftwo adjacent mobile brackets is not simultaneous.

The form 9 may then be repositioned and fixed, as was described, to theupper uprights, as well as to the secondary upright 6. Then we have theposition shown in FIG. 25e identical to that shown in FIG. 25a, but 1.50meters higher.

As is evident and as it follows moreover already from what has gonebefore, the invention is in no wise limited to those of its modes ofapplications and embodiments which have been more particularlyconsidered; it embraces, on the contrary, all variations thereof.

I claim:
 1. Self elevating form work installation with variable geometryfor making concrete surfaces or walls, particularly very high concretewalls, these walls being formed by successive lifts or constant heightover the whole length of the work until the desired height is obtained,this installation comprising essentially means for temporarily fixingworking platforms on an underlying part of the wall which has alreadybeen cast and hardened, means for shuttering the next lift over saidunder lying part, and elevating means adapted to produce self elevationof the whole of the platforms, which installation is characterized inthat said fixing means comprise series (2) of main uprights extendingsubstantially in vertical planes, these series being evenly spaced apartalong the length of the wall, said main uprights (2₁ . . . 2₄) servingessentially, on the one hand, as elements for maintaining the shutteringforms in position and, on the other hand, as means for guiding andsecuring self elevating mobile brackets supporting said platforms andtransfer means having pivot means on one side and elevation adjustmentmeans on an opposite side of at least one of said uprights. 2.Installation according to claim 1, characterized in that, in each seriesof main uprights, all the uprights except the upper upright (2₁) areanchored in the cast and hardened concrete of a number of the precedinglifts.
 3. Installation according to claim 1, characterized in that eachseries (2) of main uprights comprises a number of uprights (2₁ . . . 2₄)situated in the same substantially vertical plane, superimposeddirectly, hinged to one another and each of which is sloped to a givenangle with respect to the adjacent upright.
 4. Installation according toclaim 2, further comprising a transfer means adapted to be actuatedafter casting and to transfer the lower main upright (2₄) of each ofsaid series of uprights to position situated above the upper mainupright (2₁) of the series considered, in which position saidtransferred upright (2₄) may then be fixed with the desired slope withrespect to the immediately underlying main upright (2₁), by usingappropriate adjustment means.
 5. Installation according to claim 2,characterized in that, in each of said series (2) of main uprights, thenumber of uprights is four, each series of uprights being then anchoredin the cast and set concrete of the three preceding lifts.
 6. Theinstallation according to claim 4, characterized in that saidappropriate adjustment means comprise, on the one hand, at both ends ofsaid main uprights, a first screw spacing adjustment device (23),opposite a transverse hinge means (21) and, on the other hand a keyingsystem (18, 20), adapted to clamp two main adjacent uprights withrelative slope.
 7. Installation according to claim 1, characterized inthat said shuttering means comprise, in cooperation with the upperuprights (2₁) of said series of main uprights, secondary uprights (6)inserted on each side of wall (1) between two series of adjacent mainuprights.
 8. Installation according to claim 7, characterized in that,on a given face of the wall, each secondary upright (6) is insertedhalfway between two series (2) of adjacent main uprights. 9.Installation according to claim 8, characterized in that said series ofmain uprights (2) of one face of the wall are offset, with respect tothe series of main uprights (2) of the other face, by half the distancewhich, on the same face, separates two adjacent series (2) so that eachsecondary upright (6) on the one side of the wall (1) is locatedopposite the upper upright (2₁) of the corresponding series of mainuprights situated on the other side of the wall.
 10. Installationaccording to claim 9, characterized in that each secondary upright (6)is fixed to the upper main upright (2₁), which is facing it by means ofan assembly of fixing rods (7) traversing the space provided for thenext casting.
 11. Installation according to claim 7, characterized inthat, with said secondary uprights (6) being recoverable at each lift,each of them is extended at its lower end by a hinged extension (6'),whose slope with respect to the secondary upright properly speaking isadjustable.
 12. Installation according to claim 11, characterized inthat the hinging of the secondary upright (6) to its extension (6') isprovided by a simple bendable metal sheet (31), and in that theadjustment of their relative slope may be provided by means of a secondscrew spacing adjustment device (33) or similar, opposite said hinge.13. Installation according to claim 1, characterized in that said selfelevating mobile bracket (39) supporting said platforms (56, 57) andwhich may be guided and secured on said main uprights, are constructedin the form of hinged parallelogram structures, these structures beingassociated with means (47) for adjusting their deformation, actuatableas a function of the slope of the wall portion (1) to be shuttered,these means being adapted to maintain said platforms constantlyhorizontal.
 14. Installation according to claim 13, characterized inthat each bracket (39) comprises main front stringers (40) hingedlyconnected, by means of bearing cross pieces (42, 46), to secondary rearstringers (41), said deformation adjustment means being formed by screwadjustment stays (47) or similar extending diagonally between main (40)and secondary (41) stringers.
 15. Installation according to claim 14,characterized in that said bearing cross pieces (42, 46) comprise on theone hand first cross pieces (42), at the level of landings (43)substantially indeformable, these landings providing passage from oneplatform to the adjacent platform at the same level and secondary crosspieces (46) supporting the platforms (56, 57) respectively at the samelevels as said landings, but disposed below the preceding ones. 16.Installation according to claim 15, characterized in that each bracket(39) comprises three landings (43), two adjacent brackets consequentlysupporting three levels of platforms.
 17. Installation according toclaim 15 characterized in that in each of said landings (43) is providedwith a trap door (45) for passing from one level to the adjacent level.18. Installation according to claim 13 characterized in that eachbracket (39) comprises on the one hand a fixed arm (49), disposedbetween the main stringers (40) and adapted to bear on the correspondingmain uprights (2) and, on the other hand, a motor driven mobile arm(50), adapted to be guided on the one hand between the main stringers(40) of the bracket and on the other hand on said corresponding mainupright (2) and also to bear on said main upright at a given location.19. Installation according to any one of claims 13 to 17, characterizedin that each bracket (39) comprises an additional bearing device--withroller (48) or similar--which is disposed at its lower part, so as to beable to come to bear directly on the wall (1).
 20. Installationaccording to claim 1, characterized in that each platform (56, 57)comprises a lower platform chassis (56) and an upper platform chassis(57) extending between and bearing on two adjacent brackets (39), thesetwo chassis being free to slide with respect to each other. 21.Installation according to claim 20, characterized in that said lowerplatform chassis is formed from a frame (58) bearing on one bracket anda beam (59) bearing on the adjacent bracket, said beam being slidinglyconnected to said frame and in that said upper platform chassis (57) ismounted for bearing on the one hand on the same brackets 39 as said beam(59) and on the other hand also slidingly on the lower platform (56).